#include <iostream>
#include <cmath>
using namespace std;
int main()
{
    const double pi = 3.141592654;
    float d, D, s;
    int n;
    int m;
    cin >> n;
    while (n--)
    {
        cin >> D;
        cin >> d;
        cin >> s;
        m = pi / (asin((d + s) / (D - d)));
        cout << m << endl;
    }
    return 0;
}